NAME
mbsrtowcs - convert a character string to a wide-character string
(restartable)
SYNOPSIS
#include <wchar.h>
size_t mbsrtowcs(wchar_t *restrict dst, const char **restrict src,
size_t len, mbstate_t *restrict ps);
DESCRIPTION
The mbsrtowcs() function shall convert a sequence of characters,
beginning in the conversion state described by the object pointed to by
ps, from the array indirectly pointed to by src into a sequence of
corresponding wide characters. If dst is not a null pointer, the
converted characters shall be stored into the array pointed to by dst.
Conversion continues up to and including a terminating null character,
which shall also be stored. Conversion shall stop early in either of
the following cases:
* A sequence of bytes is encountered that does not form a valid
character.
* len codes have been stored into the array pointed to by dst (and dst
is not a null pointer).
Each conversion shall take place as if by a call to the mbrtowc()
function.
If dst is not a null pointer, the pointer object pointed to by src
shall be assigned either a null pointer (if conversion stopped due to
reaching a terminating null character) or the address just past the
last character converted (if any). If conversion stopped due to
reaching a terminating null character, and if dst is not a null
pointer, the resulting state described shall be the initial conversion
state.
If ps is a null pointer, the mbsrtowcs() function shall use its own
internal mbstate_t object, which is initialized at program start-up to
the initial conversion state. Otherwise, the mbstate_t object pointed
to by ps shall be used to completely describe the current conversion
state of the associated character sequence. The implementation behaves
as if no function defined in this volume of IEEE Std 1003.1-2001 calls
mbsrtowcs().
The behavior of this function shall be affected by the LC_CTYPE
category of the current locale.
RETURN VALUE
If the input conversion encounters a sequence of bytes that do not form
a valid character, an encoding error occurs. In this case, the
mbsrtowcs() function stores the value of the macro [EILSEQ] in errno
and shall return (size_t)-1; the conversion state is undefined.
Otherwise, it shall return the number of characters successfully
converted, not including the terminating null (if any).
ERRORS
The mbsrtowcs() function may fail if:
EINVAL ps points to an object that contains an invalid conversion
state.
EILSEQ Invalid character sequence is detected.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
mbsinit() , mbrtowc() , the Base Definitions volume of
IEEE Std 1003.1-2001, <wchar.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .